Pump by-passing assemblage



June 16, 1953 v. F. DALE ETAL 2,642,001

I PUMP BY-PASSING ASSEMBLAGE Filed Jan. 25, 1950 2 Sheets-Sheet lINVENTORS B MAE fl'ww Arron/v5 Y5.

Patented June 16, 1953 UNITED STATES PATENT OFFICE Y Y 'c,642,001;

\ PUMR BY -P AS SING ASSEMBLAGE Vernon F. Dale "and George W.Reed,nalaska, Wis., assignors to The Bump Pump 00., La

Crosse, Wis., a corporation of Wisconsin Application January 25, 1950,Serial No. 140,466

teams. (01. 103-450 conduits or the like, and relates morespecificallyto improvements in the construction. and operation -ofpositive displacement liquid propelling pumps especiallyadapted tohandle commodities such as milk.

The primary object of the present invention is to provide an improvedrotary positive displacement pump which is simple, compact and durablein construction, and. which is also highly efficient in operation.

It has heretofore been rather common practice toprovide various types ofpumps with some form of relief mechanism for by-passing fluid from thedischarge to the intake sides of the pistons when excessive pressuresare established at pump outlet or discharge. When applying such pressurerelief devices to rotary positive displacement pumps for liquid, it hasbeen customary to provide a spring pressed bypass valve operable by thepump discharge pressure and located in a liquidreturn conduit somedistance fromthe impeller displacement chamber, in order to accomplishthe desired result. While this type of relief mechanism functions 'torelease theabnormal pressures in a. fairly satisfactory manner, it isobjectionable when used in pumps for transporting commodities such asmilk which are apt to become rancid if pocketed in a confined space forany length of time, as is often the case when relatively long by-passconduits leading to and from the relief valve are employed and thisvalve is relatively complicated anddifiicult to clean the previouspressure release 7 and by-pass mechanot-opened for a prolonged period.Besides being nisms are therefore not sufiiciently sanitary and areespecially unsuitable for propelling milk and I similar delicatecommodities which-are subject-to spoilage.

It is therefore an important object of our presentinventionto provideanimproved pump; and relief unit which definitely eliminates undesirablepocketing of liquid, and which is adapted to. be

.mainta-ined in most sanitary condition at all times.

Another important object of the invention is to provide an improvedpositive displacement rotary pump having-an eifective pressure reliefdevice incorporateddirectly therein, and adapted to establish a by-passpassage of limited size,.only whenabnorinal discharge pressures areattained.

A further important object of this invention is .to provide aconveniently adjustable liquid bypass mechanism for rotary impellerpositive displacement pumps, wherein pocketing of liquid is avoided atall times, and which functions quickly and automatically to releaseabnormal liquid pressures. I Still another objectof our invention is toproaccessible for inspection and cleaning, and. which may bemanufactured and sold at moderate cost for diverse purposes. I

An additional object of the present invention is to provide a sanitaryrotary liquid pump of the double impeller type, which is composed ofonly a few simple and sturdy parts and which requires minimum attentionin order to maintain the same in effective operating condition.

These and other more specific objects and advantages of the presentinvention, will be apparent from the following detailed description.

' A clear conceptionof the improvements constituting our presentinvention, and of the construction and operation of a typical pumpunitembodying the same, may be had by referring to the drawingsaccompanying and forminga part of this specification in which likereference charactersdesignate thesame or similar parts in the variousviews Fig. l is an end view'of atypical double impeller rotary positivedisplacement liquid pump and by-pass unit constructed in-ac'cordancewith the invention; I q v Fig. 2 is a central transverse section takenthrough the unit of Fig. l along the line 2-2, and showing a by-passadjusting-wrench in dot-anddash lines; and

Fig. 3 is a fragmentary section similar to that 1 of Fig; 2, takenthrough the by-pass or pressure 'relief'mecha'nism, but showing thepressure redesire to unnecessarily restrict the utility'by' vir tue ofthis limiteddisclosure, and it ismoreover contemplated that descriptive.terms used herein be given the broadest possible interpretationconsistent with the disclosure.

Referring to the drawings, the typical double impeller rotary liquidpump and by-pass unit shown therein comprises in general, a main casingcomposed of a mid-section 6 and two opposed end closures or sections I,8 all coacting with each other to produce a displacement chamber 9having a liquid inlet conduit I and a discharge or outlet conduit I Icommunicating with the opposite sides thereof; a pair of oppositelyrotatable constantly sealingly contacting rotors or impellers I2, I3snugly confined and revolvable within the chamber 9 and adapted to bedriven by shafts I I extending through the closure section I; a rigidmovable plug or cylindrical member I5 slidably confined within a centralbore I6 formed in the closure section 8 mid-way between the conduits I0,II, and overlapping the contact zone between the impellers I2, I3; andadjustable means for normally urging the member I5 into sealingengagement with the adjacent end faces of the impellers I2, I3.

vThe three sections 6, I, 8 are adapted to be firmly but detachablyclamped to each other with the aid of studs I8 and nuts I9, 50 that theplane inner end surfaces 28, 2i of the closure sections 'I,'8-respectively will sealingly engage the adjacent end surfaces of theimpellers I2, I3; and the peripheral surfaces of the impeller lobes arelikewise sealingly cooperable with the bores 22 of the casingmid-section 5. The periphery of the rigid byepass plug or member I5 isprovided with a resilient sealing ring 23which slidably engages the boreI6 of the face plate or closure section 8, and the shafts I4 whichnormally rotate the impellers I2, I3 in opposite directions as indicatedby the arrows in Fig. 1, may be driven in any suitable manner. The outerextremities of the conduits I0, Il may also be provided with screwthreads 24 for facilitating attachment to liquid supply and dischargesources with the aid of quick-detachable couplings.

The adjustable means for constantly but resiliently urging the plugmember I5 inwardly toward the impellers I2, I3, comprises a U-shapedbracket or yoke 25 which is secured at its oppo- 4 justed bymanipulating the screw 3| with the aid of the wrench 32, so as tonormally maintain the inner face of the valve member I5 in the plane ofthe inner surface 21 of the closure plate or section 8 as in Fig. 2,thus normally producing sealing engagement between the member I5 and theimpellers I2, I3 at the zone of contact of these impellers with eachother while permitting the member I5 to move outwardly from this zone incase excessive pressure is created in the discharge space. If thedischarge pressure does e not exceed that required to displace theby-pass site ends to the casing section 3 by means of screws 25 and themedial portion of which is provided with an internally screw threadedboss 21; a helical compression spring 28 one end of which coacts with asocket 29 formed in the member I5 while its opposite end embraces andre- 4 acts against a retainer 30; and an adjusting screw 3I coactingwith the screw threads of the boss 21 and with a central recess in theretainer 30. The outer end of the adjusting screw 3| is provided with apolygonal socket to which an adjusting wrench 32 in Fig. 2, in order tovary the compression of the spring 28 and to thereby vary the pressurerequired to displace the valve member I5, and the bracket attachingscrews 26 may also be provided with similar polygonal manipulatingsockets. A lock nut 33 may also be applied to the screw 31 and caused tocoact with the boss 21 as shown, in order to maintain the retainer inadju'sted position.

When the improved pump has been properly constructed and assembled ashereinabove described, and the inlet and outlet conduits I0, II havebeen connected to a liquid transporting line with the aid of the screwthreads 24, the 1mpellers I2, I3 may be rotated by means of the drivingshafts I4 so as to cause liquid to be sucked into the displacementchamber 9 through the conduit I0 and to be discharged through theconduit II. 'The spring 28 should then be admay be applied as indicatedmember I5, this member will remain in the position shown in Fig. 2 andno pocket or appreciable clearance will exist between the impellers I2,I3

.and the relief member I5; but when the delivery pressure rises for anyreason to an extent sulficient to overcome that exerted by the spring28, the member I5. will be lifted more or less as depicted in Fig. 3 soas to permit immediate release of the excess discharge pressure byallowing liquid to return directly to the inlet space of the pump. V

It will thus be apparent that we have in fact provided acombined pumpand relief valve assemblage wherein excessive discharge pressure aboveany established value, will be quickly and automatically relievedwithout introducing objectionable pockets or space wherein liquid canaccumulate for prolonged periods of time. As soon as the abnormalpressure is disbursed, the spring 28 will immediately return the memberE5 to sealing position and will wipe out the clearance or by-pass space,so that the pump may thereafter operate normally with the impellers I2,I3 totally sealed. The packing ring 23 positively prevents undesirableescape of liquid through the bore I6 and is preferably located as nearas possible to. the inner face of the member I5 in order to eliminateundesirable pocketing of liquid; and by forming the member cylindricalmanufacture and assembly thereof are facilitated. The entire pumpstructure is durable and of utmost simplicity, and all parts thereof areobviously readily accessible for inspection and clearing thus making itpossible to maintain the assemblage in most sanitary condition at alltimes. The improved relief mechanism has proven highly successful andsatisfactory in actual use as applied to milk transporting or pumpingunits, but may be advantageously and readily applied to other types ofpumps for diverse purposes.

It should be understood that it is not desired to limit this inventionto the exact details of construction and operation of the typicalpumping unit, herein shown and described, for various modificationswithin the scope of the appended claims may occur to persons skilled inthe art.

We claim:

1. In a rotary pump, a casing having a midsection and opposed endsections secured thereto, said mid-section being provided with adjoiningparallel bores communicating at the opposite sides of their junctionwith liquid inlet and outlet conduits and both of said end sectionshaving plane parallel surfaces enclosing the opposite ends of saidmid-section bores, one of said end sections being provided with a boredisposed coaxially of said junction and having-a diameter approximatelyequal to the distance between the axes of said mid-section bores whilethe other end section is provided with spaced bearings disposedcoaxially of said adjoining mid-section bores, a positive displacementrotor mounted in each of said adjoining mid-section bores and normallysealingly engaging said end section plane surfaces and each otherbetween said inlet and outlet conduits, each of said rotors having asupporting shaft projecting from one side only and journalled inone ofsaid bearings While its opposite side is plane and devoid ofprojections, a

cylindrical piston member snugly slidably confined within said endsection bore and having a plane inner end surface normally sealinglycooperable with said plane rotor end surfaces while its outer endsurface is constantly exposed to the ambient atmosphere, and means forresiliently urging said member toward said rotors.

2. In .a rotary pump, a casing having a midsection and opposed endsections secured thereto, said mid-section being provided with adjoiningparallel bores communicating at the opposite sides of their junctionwith liquid inlet and outlet conduits and both of said end sectionshaving plane parallel surfaces enclosing the opposite ends of saidmid-section bores, one of said end sections being provided with athrough bore disposed coaxially of said junction and having a diameterapproximately equal to the distance between the axes of said mid-sectionbores while the other end section is provided with spaced bearingsdisposed coaxially of said adjoining midsection bores, a positivedisplacement rotor mounted in each of said adjoining mid-section boresand normally sealingly engaging said end section plane surfaces and eachother between said inlet and outlet conduits, each of said rotors havinga supporting shaft projecting from one side only and journalled in oneof said bearings while its opposite side is plane and devoid ofprojections, a cylindrical piston member snugly slidably confined withinsaid end section bore and having .a central outer recess and a planeinner end surface normally sealingly cooperable with said plane rotorend surfaces While its outer end surface is constantly exposed to theambient atmosphere, a helical compression spring disposed externally ofthe casing for urging said member toward said rotor and having one endconfined within said recess while its opposite end is provided with areaction plug, and means coacting with said plug for varying the tensionof said spring.

VERNON F. DALE. GEORGE W. REED.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 885,783 Palmer Apr. 28, 1908 1,694,805 Wiltse Dec. 11, 19281,927,395 Edwards Sept. 19, 1933 2,134,158 Seyvertsen Oct. 25, 19382,380,783 Painter July 31, 1945 2,434,135 Witchger Jan. 6, 19482,477,797 Girz et a1 Aug. 2, 1949

